What should always be tested for effectiveness when working in environments with potential electrical hazards?

When working in environments with potential electrical hazards, it is crucial to test the effectiveness of protective equipment. This equipment, such as insulated gloves, protective footwear, hard hats, and appropriate clothing, is designed to safeguard workers from electrical shocks and arc flash incidents. Regular testing ensures that these items are in good condition and functioning properly, thus providing the necessary protection. If protective equipment is not tested and maintained, it may not perform as expected during an electrical incident, leading to serious injuries or fatalities.

The other options do not encompass the primary focus of personal safety against electrical hazards as directly as protective equipment does. While electrical tools and machines must be regularly inspected and maintained to ensure they are functioning properly, the emphasis on protective equipment specifically addresses the individual's safety in the presence of electrical hazards. Emergency exits and lighting conditions, while important for overall workplace safety, are not as closely related to preventing injuries from electrical sources as the testing of protective equipment.